The present invention relates to a process for generating a printing image carrying a printing form on a printing form cylinder in a printing press.
A process for generating a printing form in the printing press of offset presses, especially offset presses with dampening units, with hydrophobic image areas taking the printing ink and hydrophilic areas influencing the affinity to water is disclosed in DE 4119111 A1. In this process, at least one nozzle connected to a reservoir generates small droplets of oleophilic and water resistant coating material in the form of dots or matrices adequate to the image on a hydrophilic printing form cylinder surface. The nozzle moves in line direction and the printing form cylinder is oriented perpendicular to this movement. A central control unit receives the digital image information from an information media and transfers the control signals through a transfer unit and control unit to the nozzle and the printing form cylinder.
Furthermore, the XEROX(trademark) copy process is generally known. In this process a latent image is generated on a semi-conductor drum, transferred with a powdery toner to a paper sheet and the latent image is raised. However, this process cannot be used in a printing machine.
SUMMARY DESCRIPTION OF THE INVENTION
An object of the present invention is to establish a process to generate an erasable print form on the printing form cylinder of a printing press with low expenditure and high life expectancy.
The present invention accomplishes this with a printing form cylinder having a magnetizeable surface, which can carry a magnetized image and be coated with a toner. The toner adheres to the printing form cylinder. Printing may be completed with the printing form created in this manner. After printing, the toner will be erased from the printing form cylinder with a laser.